[UT] Add Test Cases for all Event Subscription filters and actions

[mohityadav766]

Affected module
Does it impact the UI, backend or Ingestion Framework?
We are supporting various filters and actions , but the test case covers very basic scenarios.

• We need to add test case for filter and action specific scenario so that issues can be caught on early.
  This needs to be done in EventSubscriptionResourceTest.

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To Reproduce

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Expected behavior
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Version:

• OS: [e.g. iOS]
• Python version:
• OpenMetadata version: [e.g. 0.8]
• OpenMetadata Ingestion package version: [e.g. openmetadata-ingestion[docker]==XYZ]

Additional context
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